Recently, vigorous research efforts are being made in the field of a mobile phone-purpose camera module, a digital still camera (DSC), a camcorder, and a PC camera (an imaging device attached to a person computer) all connected with an image pick-up system. One of the most important components in order that a camera module related to such an image pickup system obtains an image is an imaging lens producing an image.
Previously, there have been attempts to construct an imaging lens of high-resolution by using 5 pieces of lenses. Each of 5 pieces of lenses is comprised of lenses with a positive (+) refractive power and lenses with a negative (−) refractive power. For example, an imaging lens is constructed on a structure of PNNPN (+−−−+−), PNPNN (+−+−−) or PPNPN (++−+−) in order starting from an object side. However, an imaging module of such a framework fails to show approving optic characteristics or aberration characteristics. Accordingly, a high-resolution imaging lens of a new power structure is required.